The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Internal combustion engines draw air into an intake manifold through an induction system that may be regulated by a throttle. The air in the intake manifold is distributed to a plurality of cylinders and combined with fuel from a plurality of fuel injectors creating an air/fuel (A/F) mixture. The A/F mixture is combusted within the cylinders to drive pistons that rotatably turn a crankshaft and generate drive torque.
Homogeneous charge compression ignition (HCCI) engines may operate in a plurality of modes. In a first combustion mode, HCCI engines compress the A/F mixture using the pistons until the A/F mixture auto-ignites. Alternatively, in a second combustion mode (also known as mixed-mode), HCCI engines may compress the A/F mixture using the pistons and may provide spark combust the compressed A/F mixture.